1. Technical Field
This invention relates to the field of telecommunications, and more particularly, the Session Initiated Protocol (SIP).
2. Description of the Related Art
Telecommunication systems can be time based or packet based. For example, a wireless telephone or cell phone can communicate using a time based technique such as CDMA. By contrast, the Internet is a packet based system which can support Internet Protocol (IP) telephony for allowing the real time delivery of voice and other multimedia services. Internet Telephony, also known as Voice over Internet Protocol (VoIP), allows for the conversion and transmission of voice data from a time based system into a packet based system. VoIP services are convenient in that they allow users to communicate through the Internet using a personal computer. VoIP services have also merged with the time based systems such as the standard PSTN to provide long distance telephony at reduced costs.
Internet technology is session based rather than connection based. The underlying foundation is an IP layer that makes a best effort to deliver packets, even though it provides unreliable connectionless service at the network level. SIP is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. SIP is generally used to establish an Internet session and negotiate the capabilities of the session. The sessions can include Internet telephone calls, multimedia distribution, and multimedia conferences. In general, SIP invitations are used to create sessions, and the invitations carry session descriptions that allow participants to agree on a set of compatible media types.
SIP provides signaling services for establishing and negotiating a secure and unsecured sessions but does not actually provide service offerings. Within the context of VoIP, SIP handles the call set up between devices and opens the lines, or streams, of communication. Once the session is established, SIP relinquishes control to the devices. However, during VoIP sessions, it may be occasionally, necessary to determine what actions are transpiring between the server and client. For example, during a VoIP interactive voice response (IVR) application, it may be advantageous for the client to determine if the server has properly interpreted or recognized a voice request. Debugging capabilities are not available or supported with the IETF RFC 3261 specification.
A SIP client can communicate with a SIP server to provide debug capabilities through the use of SIP MESSAGES. However, a SIP MESSAGE for debugging can only generally be used if the implementer of the SIP debugger is the same as the SIP server. What is needed is a means for standard debugging service that would allow for interoperability between SIP systems capable of supporting debug operations. Accordingly, there is a need, to provide a mechanism to SIP which allows for an interoperable session debugging service for application specific protocols that use SIP as a mechanism for session control. A need also exists, for enabling a SIP debugger for use on a SIP-enabled client that can debug any SIP compliant product.